Revised constitution of Naphtol AS-LB
Abstract
The 2-hydroxycarbazolecarboxylic acid used in the preparation of Naphtol AS-LB has been shown to be the 1-carboxylic acid and not the 3-carboxylic acid as assumed earlier. Naphtol AS-LB is therefore the p-chloro-anilide of 2-hydroxycarbazole-1-carboxylic acid.